SU1731793A1 - Method for vegetable oils chemical refining - Google Patents

Abstract

The invention relates to the oil and fat industry, and in particular to methods of physical (alkali-free) refining of oils and fats. The aim of the invention is to improve the quality of the finished product due to the most complete removal of phospholipids, heavy metals and soap. The proposed method consists in the fact that in the process of refining oils by treating with mineral acid, the removal of products of interaction of mineral acid with non-hydrated phospholipids, unreacted acid, and metals is carried out by liquid-liquid extraction of the treated oil at 40-95 ° C with an aqueous solution hydroxy derivatives of alkylenediphosphonic acids or phosphorylated derivatives of amines and their salts with complexing properties, and separation of the aqueous phase. 2 tab. with s

Description

The invention relates to the oil and fat industry, in particular to methods for the physical (alkali-free) refining of oils and fats.

The aim of the invention is to improve the quality of the finished product due to the most complete removal of phospholipids. heavy metals and soaps.

The method is carried out as follows.

Hydratable sunflower oil is treated with concentrated phosphoric acid, taken in an amount of 0.1% by weight of fat, for 30 minutes, and removal of the products of the interaction of mineral acid with non-hydratable phospholipids and mineral acid is carried out

liquid-liquid extraction at 40-95 ° C with an aqueous solution of hydroxy derivatives of alkylenediphosphonic acids or phosphorylated derivatives of amines and their salts with complexing properties, and separating the aqueous phase, the consumption of these reagents being 0.10-0.50% by weight of oil . The aqueous phase used for the extraction is taken in an amount of 5-6%, i.e. The concentration of the applied solutions is in the range of 1.6-10%.

Hydroxyethylindiphosphonic acid, nitrilotrimethylphosphonic acid or their K-Na salts are selected from the range of hydroxy or amino derivatives of phosphonic acids.

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The high stability of nonhydrating phospholipids in oil is due to their low degree of association, as well as the blocking of reactive polar groups by alkaline-earth metals (Ca, Md, etc.) and by radicals of carbohydrates and unwashed substances. Under the influence of a strong concentrated phosphoric acid, complexes of non-hydrated phospholipids with metals are destroyed to form calcium (magnesium, etc.) salts.

Subsequent treatment of the oil with an aqueous solution of the complexing agent leads to the formation of its complexes with Ca and Md, both released from compounds with phospholipids or other impurities of the oil, and in a colloid-dissolved state.

The products of the interaction of these impurities with complexing agents are removed from the oil with the aqueous phase.

Example 1 (known method). 500 g of soybean oil is treated with concentrated phosphoric acid in an amount of 0.1% by weight of the oil, the oil is mixed with acid, and then subjected to treatment at 65 ° C with a solution of potassium oleate (SpN3COOK) with a concentration of 3% in an amount of 50 g, preheated to the same temperature

After 15 minutes of stirring and 1 hour of settling, the aqueous phase with pH 7 is separated from the oil. The resulting oil has an acid value (r.p.) 3.1 mg KOH / r, the residual phosphatide content is 0.072%, the soap content is 0.02%, does not contain free acid,

During processing, the formation of an emulsion layer and the ingress of soap into the treated oil are observed (Table 1).

Example 2. 500 g of soybean oil is treated with concentrated phosphoric acid by a known method, after which the oil is treated (liquid-liquid extraction) with hydroxyethylidene diphosphonic acid solutions of various concentrations, based on the reagent consumption of 0.05-0.60% to the treated oil. Process temperature 60 ° C.

The results indicate that 0.10-0.50% HEDP provides for the almost complete removal of phospholipids from the oil to a residual content of 0.02-0.03% and trace metals (to a residual iron content of 0.05-0.08 mg / kg and copper 0.00-0.01 mg / kg.

Example 3. 500 g of rapeseed oil is treated according to the known and proposed methods described in examples 1 and 2. Comparison of the results

shows the possibility of not only deeper extraction of phospholipids and metals in the case of treating the oil with a complexing agent, but also increasing

the output of the raffinate (table. 1).

Example 4. 1000 g of sunflower oil refined by the proposed method. The results are shown in Table. one.

The resulting refined oil is not

contains phospholipids and traces of copper, the residual iron content is 0.08%, characterized by relatively low color: 0.9 red with 35 yellow Lovibond,

EXAMPLE 5 1000 g of soybean oil are treated under acceptable conditions with a solution of nitrile trimethylphosphonic acid, its trisodium salt, and the K-Na salt of hydroxyethylidene diphosphonic acid. Data

Table 1 demonstrates the high efficiency of the tested reagents.

Example 6. 1000 g of soybean oil with a non-hydratable phospholipid content of 0.27% is treated according to

The proposed method is a solution of hydroxyethylidenediphosphonic acid in the temperature range 30-95 ° C.

The data table. 2 shows that when the process temperature is less than 40 ° C, the efficiency of removing phospholipids and metals from oil is impaired; the upper limit is limited to the use of aqueous solutions of reagents. Thus, the optimal interval should be considered 40-95 ° C.

As can be seen from the table. 1 and 2, the lower and upper limits of the consumption of complexing agents are selected on the basis of the following. Thus, when the specific consumption of the reagent is less than 0.10% by weight of the fat, the conditions of the process undergo deterioration, the full reaction of its interaction with the listed impurities is not ensured with the formation of products removed from the aqueous phase. A further increase in the consumption of the complexing agent of more than 0.5% by weight of the fat does not affect the efficiency of the process,

Thus, the quality of the finished product is improved due to the most complete

removal of phospholipids, heavy metals, and soap.

Claims (1)

The invention of the method of physical refining of vegetable oils, including the treatment with mineral acid, followed by the removal of the products of the interaction of mineral acid with non-hydratable phospholipids and other impurities of the oil and residual mineral acid by liquid-liquid extraction at 40-95 ° C, followed by separation of the aqueous phase, characterized in that, in order to improve the quality of the finished product due to the most complete removal of phospholipids, heavy metals and soap, the removal of interaction products is carried out with aqueous solutions of complexing agents. substances selected from the range of hydroxyethyl diphosphonic acid or nitrile trimethylphosphonic acid, or their potassium-sodium salts, and the complexing agent is taken in an amount of 0.1-0.5% by weight of the fat. Table 1 Famous Soy 3.10 Offered - Limy Rapeseed 2.50 Proposed Rapeseed SunflowerFamous 3.00 0.072 6.10 0.07 98.5 Proposed Famous The proposed 2.50 0.03 0.04 0.00 97.8 0.27 6.1 (0 0.08 0.040 , 31, 70 0.09 0.05 0.10 0.20 0.30 0.50 0.60 0,007 0,000 0,000 0,000 0,000 0,000 0,060 PED4 0.20 0,000 Continued table. one Emulsion formation is observed Emulsion formation is observed Retive0  .50 n 41 H, 7P0.16 n o, 90 2.15 Q.03 0.08 0.00